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báo cáo khoa học: "Evolutionary relationships based on in the Sativa group of Oryza isozyme data"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Evolutionary relationships based on in the Sativa group of Oryza isozyme data | Génét. Sél. Evol. 1985 17 1 89-114 Evolutionary relationships in the Sativa group of Oryza based on isozyme data Gérard SECOND O.R.S.T.O.M. Institut Francois de Recherche Scientifique pour le Développement en Cooperation Present address Unite de Biologie des Populations et des Peuplements C.N.R.S. Centre Louis Emberger B.p. 5051 F 34033 Montpellier Cedex Summary The wild and weedy species of the Sativa group of Oryza were studied for their isozyme polymorphism at 24 loci for 181 plants each taken in a different population the total representing the entire area of pan-tropical distribution. One to 10 electromorphs were distinguished per locus with an average of 4.1. A multivariate analysis of the data on an individual strain basis showed several important discrepancies with taxonomy based on morphological characters. In particular the Australian form was largely divergent from the Asian and American forms of o. rufipogon which were closely related to each other and to o. breviligulata. A Chinese form of o. rufipogon could be distinguished from a South Asian form although many intermediates existed. The South Asian form of o. rufipogon was the most variable of all although it was not possible to distinguish the annual from the perennial life forms at the isozyme level. The electromorph frequencies and the distribution of genetic distances in 2 by 2 strain comparisons were analysed within and between the geographic groups or species. Large values of Nei s genetic distances up to 1.26 and large proportions of loci with no allele in common up to 9 out of 24 were found between groups The closest relationships of the 3 basic isozyme patterns of indica japonica and glaberrima cultivated rice were found with South Asian o. rufipogon Chinese o. rufipogon and o. breviligulata respectively. It was concluded that the Sativa group was composed of 2 species endemic to Africa o. longistaminata and o. brevili-gulata and a complex species o. rufipogon with South Asian Chinese New .